In the exploration of oil, gas and geothermal energy, drilling operations are used to create boreholes, or wells, in the earth. Drilling rigs used in subterranean exploration must be transported to the locations where drilling activity is to be commenced. These locations are often remotely located in rough terrain. The transportation of such rigs on state highways requires compliance with highway safety laws and clearance underneath bridges or inside tunnels. Once transported to the desired location, large rig components must each be moved from a transport trailer into engagement with the other components located on the drilling pad.
Moving a full-size rig requires disassembly and reassembly of the substructure and mast. Safety is of paramount importance. Speed of disassembly and reassembly is also critical to profitability. Complete disassembly leads to errors and delay in reassembly. When the substructure is assembled over the drilling pad, the mast is connected to the drill floor above the substructure. Each substructure side box is pin connected to its respective substructure base box. The drill floor center section is connected between the driller's side box and the off-driller's side box. The lower section of the mast is pin connected to the drill floor. The center mast section is pin connected to the lower mast section and the upper mast section is connected to the center mast section.
When the mast sections are connected together, the mast is raised by pivoting it on the pin connection to the drill floor. It is critical that the driller's side boxes remain secured to the base boxes during mast raising. Failing to properly secure them together results in their separation and collapse of the mast with significant damage to the entire structure and risk of injury or death to personnel. Once the mast has been raised over the drill floor, the side boxes are unpinned to disconnect then from the base boxes. Only then can the substructure can be raised.
It is desirable to have a connection system that is automated, to reduce rig-up and rig-down time. It is desirable to have a system that can be manually unlatched, and that automatically resets itself upon substructure raising. It is also desirable to have a system that latches automatically to speed the operation and to prevent accidents when an employee forgets to pin the side box to the base box. It is also desirable that the connection and disconnections be performed without the need to align the dog-ears (pin holes) for insertion of a pin.
More particularly, it is desirable to provide a substructure lock mechanism that cannot be left open when the side box is away. It is also desirable to provide a substructure lock mechanism that will automatically reset itself in a fairly short distance of raising the side box above the base box, such that if necessary to bring the side box back down for any reason during raising, the lock mechanism will re-engage.
The preferred embodiments of the present invention provide a unique solution to the engineering constraints and challenges of providing a rapid, safe, and reliable connection between the drill floor and substructure of a drilling rig.